1. Field of the Invention
The invention relates to an aircraft fuselage having a rear end opening for cargo despatch and is primarily concerned with a pressurisable fuselage which will facilitate the despatch of an item of cargo, particularly an elongate item of cargo.
2. Discussion of Prior Art
For many years it has been known to provide a large rear opening door arrangement at the rear of a freighter aircraft fuselage which operis the entire storage area of the fuselage to enable cargo stored in the aircraft to be despatched when the aircraft is in flight. Typically, bulky equipment such as crates of supplies and even vehicles can be despatched from the aircraft in that way. The aircraft is usually of a pressurised type and the cargo despatch is carried out at a relatively low altitude where the door arrangement can be opened with the fuselage de-pressurised. The use of a large rear opening door arrangement requires the use of an airframe of sufficient strength to minimise distortion due to the lack of structure in the doorway and to the weight of the doors when they are opened in flight. Also, where a passenger aircraft is adapted to carry freight, the use of a large rear door arrangement would involve major modifications to the aircraft which is obviously undesirable.
The present invention is concerned with the despatch from an aircraft of elongate items of cargo having a relatively small transverse dimension and is primarily concerned with an aircraft having a pressurisable fuselage which will enable such despatch to be carried out in an efficient manner.
According to a first aspect of the invention there is provided a pressurisable aircraft fuselage including a cargo storage compartment, a rear bulkhead for the compartment for withstanding internal air pressure in the fuselage, a closeable opening in the rear bulkhead through which an elongate item of cargo can be passed, and an opening in the rear of the fuselage through which the said item passes to be despatched from the aircraft with the fuselage de-pressurised.
The use of the closeable opening in the bulkhead means that an elongate article of relative small transverse dimension can easily be passed longitudinally through the opening for despatch from the aircraft. Moreover, to adapt a passenger-carrying aircraft to carry such cargo, a modification to the bulkhead involves a relatively straightforward modification compared to that involved in providing a large opening door arrangement as described above.
The closeable opening preferably has a door which is moveable between open and closed positions, for example by sliding. The door preferably contacts seal means when in its closed position. In such a case, pressure in the compartment may normally be arranged to press the door against its seal means.
Guide means may be provided for guiding the elongate item of cargo at least from the cargo storage compartment through the closeable opening to the opening in the fuselage. At least part of the guide means may be positioned such that the cargo will depend therefrom when being guided. Alternatively or additionally, part of the guide means may provide sideways support for the cargo when being guided. The guide means may comprise at least one rail. If desired, the guide means can be inclined at any angular orientation, whether up and down or side to side, in relation to the straight and level flight direction of the aircraft.
In one embodiment the guide means may firstly guide the item of cargo from a storage location in the fuselage to a said closeable opening and thereafter guide the item through the closable opening to the opening in the fuselage.
In this embodiment the guide means may include rails which are interrupted in the region of the closeable opening with co-operative runners optionally adapted to carry the item of cargo and being staggered so as always to support the cargo during guidance even when one runner is passing between lengths of rail.
The runners may have wheels and may be rigidly attached to a cargo support.
The guide means may be powered, for example as by electrical or pneumatic or hydraulic power, or may rely upon gravity and/or human intervention to achieve movement of the item of cargo.
In a preferred embodiment, the bulkhead has a number of closeable openings therein to enable the elongate items of cargo to be despatched from the aircraft via each closeable opening, for example simultaneously. In such a case, a number of openings may be provided in the fuselage to correspond with the closeable openings in the bulkhead.
The or each opening may conveniently be positioned on a rear underside portion of the fuselage. In that way, a modification to an aircraft to define the openings is less likely to interfere with tailplane mounting arrangements on certain aircraft.
The or each opening in the fuselage may be closeable by suitable doors. However, unlike the large door arrangement of know types of freight aircraft, each door, by virtue of its end location and the shape of the cargo, can be relatively small to enable the elongate item of cargo to be despatched therethrough. In this way expensive structural reinforcement to the fuselage to compensate for large door openings can be avoided.
In a preferred embodiment, the or each opening in the bulkhead is arranged to one side of a keel beam for the fuselage.
In order to facilitate loading of the elongate item of cargo into the fuselage, the fuselage may have a further closeable opening therein which may itself be elongate. Such an opening may conveniently be positioned near the front of the fuselage and may comprise an existing fuselage loading door. Where existing pressurised fuselages are being adapted according to the invention this feature additionally enables the invention to be realised at the lowest cost and by adding minimal weight to the aircraft.
According to a second aspect of the invention there is provided an aircraft having a fuselage according to the first aspect of the invention or any of the consistory clauses relating thereto.
According to a third aspect of the invention there is provided a method of despatching an item of cargo from a pressurised aircraft fuselage, the method including the steps of de-pressurising the fuselage, opening a door in a rear pressure bulkhead of the fuselage and passing the item of cargo through the doorway to despatch it from the aircraft.